title: The genome of tolypocladium inflatum: evolution, organization, and expression of the cyclosporin biosynthetic gene cluster.
abstract: The ascomycete fungus Tolypocladium inflatum, a pathogen of beetle larvae, is best known as the producer of the immunosuppressant drug cyclosporin. The draft genome of T. inflatum strain NRRL 8044 (ATCC 34921), the isolate from which cyclosporin was first isolated, is presented along with comparative analyses of the biosynthesis of cyclosporin and other secondary metabolites in T. inflatum and related taxa. Phylogenomic analyses reveal previously undetected and complex patterns of homology between the nonribosomal peptide synthetase (NRPS) that encodes for cyclosporin synthetase (simA) and those of other secondary metabolites with activities against insects (e.g., beauvericin, destruxins, etc.), and demonstrate the roles of module duplication and gene fusion in diversification of NRPSs. The secondary metabolite gene cluster responsible for cyclosporin biosynthesis is described. In addition to genes necessary for cyclosporin biosynthesis, it harbors a gene for a cyclophilin, which is a member of a family of immunophilins known to bind cyclosporin. Comparative analyses support a lineage specific origin of the cyclosporin gene cluster rather than horizontal gene transfer from bacteria or other fungi. RNA-Seq transcriptome analyses in a cyclosporin-inducing medium delineate the boundaries of the cyclosporin cluster and reveal high levels of expression of the gene cluster cyclophilin. In medium containing insect hemolymph, weaker but significant upregulation of several genes within the cyclosporin cluster, including the highly expressed cyclophilin gene, was observed. T. inflatum also represents the first reference draft genome of Ophiocordycipitaceae, a third family of insect pathogenic fungi within the fungal order Hypocreales, and supports parallel and qualitatively distinct radiations of insect pathogens. The T. inflatum genome provides additional insight into the evolution and biosynthesis of cyclosporin and lays a foundation for further investigations of the role of secondary metabolite gene clusters and their metabolites in fungal biology.
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Bushley
authors.forename: Rajani
authors.initials: R
authors.lastname: Raja
authors.forename: Pankaj
authors.initials: P
authors.lastname: Jaiswal
authors.forename: Jason S
authors.initials: JS
authors.lastname: Cumbie
authors.forename: Mariko
authors.initials: M
authors.lastname: Nonogaki
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Boyd
authors.forename: C Alisha
authors.initials: CA
authors.lastname: Owensby
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Knaus
authors.forename: Justin
authors.initials: J
authors.lastname: Elser
authors.forename: Daniel
authors.initials: D
authors.lastname: Miller
authors.forename: Yanming
authors.initials: Y
authors.lastname: Di
authors.forename: Kerry L
authors.initials: KL
authors.lastname: McPhail
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Spatafora
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000382:microbiology*; D016572:Cyclosporine / Q000378:metabolism*; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D016678:Genome; D006999:Hypocreales / Q000201:enzymology / Q000235:genetics*; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D017423:Sequence Analysis, RNA
chemical_list: D009097:Multienzyme Complexes; C048525:cyclosporin A synthetase; D016572:Cyclosporine; D010453:Peptide Synthases